The J-20 prototypes have Russian-built AL-31F or domestic WS-10 engines designed for fourth-generation fighters like the Russian Su-27 and Chinese J-10. Because the J-20 cannot achieve supersonic flight or supermaneuverable performance with either of these engines, the aircraft does not qualify as a fifth-generation fighter despite its stealth capability.

It took Lockheed Martin 16 years to put the F-22 Raptor into service after the aircraft's first flight in 1998. It spent another 15 years to have F-35 Lighting II ready for service. Russia will put its T-50 stealth fighter into service next year after its first flight in 2010. If China can get the J-20 ready for action by next year, it will set a record by achieving the feat in just five years.

The F22 has 51% more thrust with 26000 lbs vs 17125 lbs for the J-20.
The F22 has 27% thrust with afterburners at 35,000 lbs vs 27000 lbs for the J-20.